Caption: Campylobacter bacteria. Coloured transmission electron micrograph (TEM) of two Campylobacter rectus bacteria. These Gram-negative rod-shaped bacteria have single flagellum (hair-like strand) that is used for movement. This species is strongly associated with periodontal diseases, including gingivitis and periodontitis, in humans. Periodontal diseases are due to infections of the gum tissues around the teeth. They eventually lead to loosened and lost teeth due to a lack of support by the gums. C. rectus infections can be prevented by using antibacterial toothpastes and mouthwashes. Treatment is by professional cleaning and the insertion of wafers containing antibiotics beneath the gumline. Magnification: x27,000 when printed 10 centimetres high.